Features explained
Which? explains the LCD and plasma TV features to look for. Get to grips with the jargon before you buy an LCD or plasma TV.
Which? explains the LCD and plasma TV features to look for. Get to grips with the jargon before you buy an LCD or plasma TV.
The beauty of LCD and plasma TVs is that they're much slimmer than conventional TV (about 20cm to 30cm deep compared with 50cm to 60cm deep for a 32-inch conventional set with a cathode ray tube).
LCD and plasma TVs take up less space, have bigger screens, can be mounted on walls and look incredibly stylish.
Most of us watch standard-definition TV images. These are made up of 576 horizontal lines stacked up to form a picture.
HDTV is a new system that transmits a TV signal with roughly twice the standard picture resolution as normal standard-definition telly. Both Sky (satellite) and Virgin (cable) operate HDTV channels.
To watch HD content on your LCD or plasma TV, you need a subscription to either one of these services and an 'HD-ready' TV. However, not everything on the dedicated HD channels is actually recorded in HD. More programmes are being recorded in HD all the time but content can be thin on the ground.
More free HD content is on the way. The BBC is set to launch a new satellite service in 2008 called Freesat. You'll need a dish and a new set-top box to watch the 80 digital channels plus a couple of HD channels.
Plans are also afoot to launch HDTV channels on terrestrial Freeview. Details are still sketchy but your LCD or plasma TV will need to be HD-ready TV, and you'll need a special digital box to receive the HD content.
Without this box, no currently-available IDTVs, PVRs or set-top boxes will be able to receive the new channels.
HD-ready LCD and plasma TVs
The HD-ready label means the LCD or plasma TV has the minimum screen resolution of at least 720 horizontal lines and digital sockets (HDMI or DVI) to receive and display a 720p or 1080i HD picture.
A third standard called 1080p boasts marginally sharper pictures. But there are no 1080p broadcasts and it's only available via high-definition DVD formats.
HD-ready 1080p
This official logo from EICTA (the same people behind HD-ready ) means the LCD or plasma TV has a high screen resolution of 1080 horizontal lines (1920x1080), can process a 1080p HD signal and refresh the screen at 24 frames per second – meaning it's compatible with high-definition DVDs.
Similar-sounding and -looking logos such as, HD Full, 1080HD or 1080HD-ready are also commonplace, but they don't guarantee high definition DVD compatibility and exact meanings can differ between manufacturers. So be careful and look for the exact match when buying your LCD or plasma TV.
24fps
In the absence of the official HD-ready 1080p logo, check for labels like this on LCD and plasma TVs. It isn't an offical EICTA standard but does mean the LCd or plasma TV should process a 1080p signal and screen high-definition DVD without juddering images.
Some LCD and plasma TVs (including most of the Panasonic LCD TV Best Buys) claim to be neither HD-ready 1080p nor sport logos like 24fps but still work well with high-definition DVD, thanks to their superior digital processing software.
Which? is carrying out additional tests on older HD-ready TVs to see which are suitable for use with high-definition DVD players.
Digital tick, Freeview or DVB
The digital tick is an assurance that the LCD or plasma TV will work after the digital switchover. In reality the logo costs manufacturers money, so it’s not widely used. DVB and Freeview logos mean the LCD or plasma TV has a digital tuner built-in.
LCD and plasma TV screen resolution
This is the number of lines or pixels on screen (width x height). But a good TV picture often relies more on decent digital processing software. Most of the Panasonic Best Buy LCD and plasma TVs don’t come with the highest screen resolution but still have the best standard-definition pictures.
LCd and plasma TVs with digital processing
Many of the fancy-sounding labels refer to the digital-processing software used by LCD and plasma TVs. Philips uses Pixel Plus and Panasonic Vreal².
Decent processing software usually equals good pictures. For instance, most new Panasonic LCD and plasma TVs feature Vreal² and they all have decent pictures.
100Hz
This is one of the newest logos. It means an LCD or plasma TV has digital-processing software, which should make panning and motion sequences marginally smoother.
Colours
When a manufacturer claims an LCD or plasma TV can display more colours, it’s unlikely you’ll actually see more colours on screen. However, it's a sign of faster processing technology and potentially better picture quality.
This is the number of pixels or lines displayed on the screen. Expressed as width x height, the highest screen resolution currently available is 1,920x1,080.
This is desirable for use with high definition material but it doesn't necessarily equate to the best pictures for watching normal TV broadcasts or DVDs. A good LCD or plasma TV often relies far more on decent digital processing software.
The shape of the screen (width x height). Most LCD and plasma TVs are now wide-screen with an aspect ratio of 16:9. Older TVs and some portables have an aspect ratio of 4:3. Digital TV is broadcast in a widescreen format.
It's a good idea to choose a widescreen LCD or plasma TV that automatically alters how different broadcasts are displayed – eg showing standard (4:3) broadcasts with black bands on either side so the images aren't stretched out of proportion. Most widescreen LCD and plasma TVs will do this.
Picture-in-picture displays a small image in the corner of the screen while you watch the main image. Some LCD and plasma TVs let you watch another broadcast channel in this way – so you can check the progress of a match, say.
However, with many of the LCD and plasma TVs in the Which? test, the picture-in-picture system lets you monitor only those pictures from external equipment, such as a DVD player or set-top box.
With the popularity of digital cameras and photos stored on CDs, LCD and plasma TVs are increasingly used for 'slide-shows'.
The main ways to display digital photos on screen are by connecting your digital camera to one of the TV's audio-visual (Scart or phono) inputs, or by watching picture CDs via a DVD player. Some LCD and plasma TVs come with memory card slots that let you plug the card from your digital camera directly into the TV.
Electronic Programming Guide (EPG)
Found on all IDTVs, this is an on-screen channel guide showing programming for the week ahead – a bit like having an electronic copy of the Radio Times at the touch of a button, on your LCD or plasma TV screen.
The style and format of an EPG depends on the particular model of LCD or plasma TV but most show programmes at least seven days ahead, plus a 'Now and Next' option.
The best EPGs show several channels over a fixed time period, say two hours, making comparing channels and planning an evening's viewing more convenient. Some also display a handy 'picture-in-picture' of the current channel.
An additional narration for visually-impaired people that describes significant visual information, such as body language and scenery. The service is available on Sky and Freeview.
Only a few of the latest LCD and plasma TVs (mostly Panasonic and Sony) can decode audio description on Freeview. A schedule of Freeview programmes with audio description on the DTG website.
With a set-top box or integrated digital TV, you can access the digital text services available on some digital channels. These look like internet pages, and some let you watch an inset of the TV picture at the same time.
This is the socket for your aerial and allows the broadcast signal to be received by your tuner.
Scarts are the best way to connect equipment like DVD players and VCRs to your TV. Most LCD and plasma TVs come with at least two Scart sockets. If you need more, you can buy a Scart switching box for £10 or so to expand your LCD or plasma TV's capacity.
For the best picture, look for Scarts that support the high-standard RGB signal. This splits the video signal into its red, blue and green components to give an improved picture.
If you're short of Scart inputs, composite video and s-video are an alternative. S-Video signals are split into colour and brightness but are slightly inferior to Scart RGB.
Composite video (usually a yellow phono socket) is the lowest-quality video connection.
Both let you plug other AV equipment, like camcorders and games consoles, directly into your LCD or plasma TV.
If you're interested in HD this is the high-capacity input for high-definition video and audio signals.
Two HDMI sockets mean you could plug in both an HD set-top box and an HD DVD player to your LCD or plasma TV.
An analogue VGA input lets you connect your PC – effectively turning your LCD or plasma TV into a PC monitor. Some LCD and plasma TVs can also be connected via a digital input. This can either be a DVI socket or now more commonly a HDMI input configured to support PC screen resolutions.
This is a high quality video input made up of three sockets coloured red, green and blue. Also known as YPbPr, it splits the video signal into three separate parts for an improved picture on your LCD or plasma TV.
However, component connections are still not widely used on AV equipment and unlike Scart sockets they don't carry the widescreen switching signal.
These red and white sockets allow you to connect your LCD or plasma TV to a stereo amplifier – useful if the built-in speakers aren't quite up to the job.
Many LCD and plasma TVs have 'virtual' surround sound: they mimic the effect using the two main speakers, but this is usually disappointing. The best solution for good-quality surround sound is a dedicated home cinema system.
If you want to connect your LCD or plasma TV directly to a surround sound system there are two types of digital connections – coaxial (wire) and optical (fibre optic). Make sure your surround sound system input matches the input on your LCD or plasma TV.
However, digital surround-sound on Freeview is virtually non-existent, so to make use of the socket, surround-sound signals from other pieces of equipment (like DVD players or Sky boxes) have to be channeled through the TV via the HDMI input – a handy trick that only works on some LCD and plasma TV models.
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